420 has four prime factors: 2 3 5 7.
Two factors.
210 with factors of 2, 3, 5, and 7
Factors of 7 are 1 and 7.
420 has four prime factors: 2,3,5,7
7 has two different factors. 9 has three different factors. 10 has four different factors. 16 has five different factors. So, the answer is 10.
420 has four prime factors: 2 3 5 7.
Four of them which are: 1, 7, 13 and 91
There are four.
Seven factors.
Two factors.
Two factors.
30 has 7 factors
510510
Factors of 28 in three different ways are: 14*2, 7*4, 7*2*2 and remember also 28*1.
7 has two factors, one and itself. For them to be common, they need to be compared to another set of factors.
Four